Flip Panic!
Easy to learn, hard to master - a puzzle game unlike any that you've played before! It starts simple enough, but the rules change from level to level, and new elements are introduced making a very simple game have infinite replay value. 5 game difficulty levels, 2 quick fix 'Blitz! ... Check it out! ... ' games, and 50 total levels.
http://www.midnightryder.com/Binaries/setupfpdemo.exe - 5Mb - Download - Screenshot

Sudoku Challenge
If you're a fan of the new Sudoku puzzles that are sweeping the country, or would like to learn about these fascinating puzzles, you'll really enjoy our new Sudoku Challenge. With a single click, you can create your own puzzles with up to 5 levels of difficulty. ... Top 10 High Score List for each level of difficulty. ... You can solve puzzles on-screen, with no need for a pencil and eraser, print puzzles and lots more 5 levels of difficulty (Very Easy, Easy, Medium, Hard, Very Hard). ... Billions of puzzle combinations generated by the computer Customizable menu position (Left or Right)...
http://69.60.111.87/downloads/t/sudokuchallenge1.0.zip - 1Mb - Download - Screenshot

Paraben's Reversum
Paraben's Reversum is an eye-catching version of the challenging game known as othello or reversi. The object of the game is to turn as many of the opponent's tiles over as you can. Play against the computer, another person, or over the Internet. Save & load games, view graphs & instant replays... Choose from three different difficulty levels, but be prepared for a challenge as even the easiest difficulty level is not so easy. ... Reversum, before they reverse you!
http://www.paraben.com/programs/reversum.exe - 927Kb - Download - Screenshot

Connect
Connect is a one or two player strategy game with three levels of difficulty. Connect the dots to close the grid cells, just like us older kids did on paper back in the olden days. Each cell on the playing field has 4 sides. Click on a side to close the side. ... The computer is easy to trick when playing the EASY level, but it is not so stupid on the hardest level. ... TOP-10 scores are recorded for all difficulty levels. ... All Windows versions need: 80486+, 16+ colors, 1 Meg on hard drive. ... There are Surprise cells that can have plus or minus points.
http://wcarchive.cdrom.com/pub/bws/bws_105/connec20.zip - 992Kb - Download - Screenshot

MasterWord
CFB MasterWord is a Palm word game similar to Mastermind and Jotto. It will appeal to anybody with a good knowledge of words and logical reasoning skills. The free trial version is intended to be easy enough for children to play while still providing a good mental challenge. ... It contains more than 1500 unique words to guess and and has an additional four levels of difficulty. ... It has ten different words to guess and two levels of difficulty. ... There are several different levels - the harder the level, the higher is your potential score.
http://www.cfbsoftware.com/palmfiles/masterword.zip - 31Kb - Download - Screenshot

Switcheroo Deluxe
The object of Switcheroo Deluxe is to click on sets of the same color in numbers of 2 or more to clear sections of the game screen. You can advance levels by clicking on "Level Up" at the top of the window if your points match or exceed those pre-determined to qualify for the next difficulty level. ... If you get stuck you can select "Reset" from the file menu which will scatter the olored boxes in another order so as to make more moves possible.
http://www.myaddictinggames.com/sdsetup.exe - 395Kb - Download - Screenshot

Spider Solitaire
Spider Solitaire is the most fun solitaire game that is played with 104 cards in ten playing stacks. The object of the game is to remove all of the cards from the ten playing stacks. This Spider Solitaire games has two difficulty levels with one, two and four suites. ... Usually, it takes about 10 to 30 minutes to play the game for one round, depending on the selected difficulty level.
http://www.villemobile.com/games/bindemo/vmspider2_demo.prc - 107Kb - Download - Screenshot

Nine Men's Morris
Play a challenging three-in-a-row strategy game! Nine Men's Morris is an exciting capture and defend strategy game that is endlessly entertaining. If you like chess or checkers, you will love this award winning classic. Place your pieces to make mills-three pieces in a row, horizontally or... Features Supports Palm OS 5 Stunning Hi-Resolution color graphics Five difficulty levels Learn how to play on the Trainee level! ... it could be a trap! ... Try a FREE Download of this timeless classic for your Palm OS device today!
http://www.smartboxdesign.com/palm/9menm113.zip - 86Kb - Download - Screenshot

Hyper 21
Do you like the strategy of Black Jack? Do you like the fast paced action of Tetris that keeps you on your toes? Hyper 21 offers the best of both worlds! The dealer constantly deals out cards filling up the playing area. You have to make 21s fast enough to prevent the cards from reaching the... Each level has a number of 21s required to complete the level. ... With unlimited levels there is always a more challenging level to reach. ... Every 20 levels is a race level where the dealer will deal nothing but 10's and Aces and you must get 100 21's as fast as possible!
http://www.nutrigames.com/Hyper21/Hyper21SharewareInstaller.exe - 7Mb - Download - Screenshot

Vocaboly
Vocaboly is a learning software for English vocabulary, especially for TOEFL, GMAT, GRE, SAT test takers, through many learning methods, including test and game, memorizing will be much easier and more efficient, above all it's fun. Main Features [Big Vocabulary] Vocaboly contains five books:... [Word Difficulty Level] Each word can be assigned to a difficulty level from 0 to 5, the default difficulty level is 0. ... You can learn the words in whatever difficulty level you choose. ... [Multi-Level Study Methods] Word Ticker : Display words automatically.
http://www.vocaboly.com/download/VocabolySetup.exe - 3Mb - Download - Screenshot