Hi! I am enjoying my first Ludum Dare Game Jam: in addition to combining my efforts with my teammates to produce a nicely finished entry, I got to play quite a few games that had interesting concepts. I've already rated 50 games, and I thought it would be a good time to share some of my favorites, as well as share some of my insights into the theme!

Limitted Space...Bars?

When I saw "limitted space," I thought of space as the resources a player has in order to achieve some goals. This can be literal space, such as the area in an action game where the player can move, or it can be more functional space, such as the space in a backpack, which actually represents a limited amount of props, or it can be a tricky way (which is what we did lol) to think of space as the space bar, which is tied to a specific function that helps the player achieve a goal and limits the use of the space bar.We've also found platformers that use similar mechanics when rating other people's games, with my favorites being Gyronimo made by pepnou (@pepnou) *, and enderswype (@enderswype), which sets the spacebar to function as a reverse gravity and cleverly adds 90° flip gravity to left-to-right without increasing the number of action number of buttons to include a 90° flip gravity to the left and right, and gives separate counts for reverse gravity and 90°flip gravity. If you're a fan of platform jumping games that like a challenge, I think you'll enjoy the challenging yet very shuffling puzzles in this game.
Gyronimo | ldjam.com | Ludum Dare game jam

To Make Limit Fun

This concept of "limiting player's resources" sometimes go with problems: some games seem to have very tiresome limitations to some very basic and important mechanics: maps that are too large, movement that is too cumbersome, and backpacks that are too small. Some restrictions only add to the repetitive gameplay, increasing the length of play and boring the player. But there are limitations that force the player to be more strategic: I saw a lot of interesting Sokoban-like puzzles, and I saw a lot of interesting gameplay design by limiting the game screen. One of the restrictions that I found most interesting to me was Please Sign Here by Lunea (@lunea), Markadia (@markadia), and Ampo (@ampo).It asks the player to sign a document and places diverse restrictions on the signature - at first it's the number of strokes, the number of intersections, the total length, etc., and later in the level the restrictions really made me laugh out loud.
Please Sign Here | ldjam.com | Ludum Dare game jam

Concise and Engaging Confrontation

Another solution would be to keep down the idea of "adding limit to the core gameplay" and stress "confronting the limits" as the core gameplay，and make it concise and engaging. I highly recommend:
Packed to the Gills! by npckc (@npckc)*, nomnomnami (@nomnomnami), DonutShoes (@donutshoes), Hunter Van Brocklin (@hunter-van-brocklin), and chunderfins (@chunderfins).It In the game you play as a fish trying to squeeze into a crowded train, concentrate on using your various poses to try to fit right in the limitted space. The game has a very cute art style, progressive but streamlined control. Very easy to start and fun!

Too Maneon Loots by Pierre-Marie (@pierre-marie), Ladylpcr (@ladylpcr), and lastuck (@lastuck). In this game you'll have to deal with a stream of gear coming into your backpack using only your mouse while your character are automatically fighting the monsters. If you don't get rid of it in time, too many props or junk will burst your backpack and end the game for you. I like how some of the details of the game make me feel like I have my hands full (e.g. the backpack space gradually cracks if you don't make room for it in time, and the trash cans start to move in the later stages of the game).
Packed to the Gills | ldjam.com | Ludum Dare game jam
Too Maneon Loots | ldjam.com | Ludum Dare game jam

Manipulate Space

Some developers have removed the "limit" and given players the ability to manipulate space instead of being passive, which may sound a bit off-topic, but there are some interesting game designs that come out of this concept! In which I highly recommend Compress(space) by Fahim Faysal (@fahim-faysal) And Stretchmancer by TobiasD (@tobiasd), Ludumer1986 (@ludumer1986), and Choo (@choo) Both have cool mechanics and well-polished stages!
Compress(space) | ldjam.com | Ludum Dare game jam
Stretchmancer | ldjam.com | Ludum Dare game jam

What's more...

I've only mentioned a few games that I found to have really interesting concepts related to my insights, and there are actually a lot more games that I'd like to recommend which are cool in many aspect. I'd like to post some of my other recommendations in the future. Feel free to leave comments. I have little experience in game development yet so I'd like to hear you guys' ideas. And also feel free share some your recommends or your games! (I may rate them if I have time)
Check our game too! We made a puzzle platformer with fun plots and cute art！
Space Bar ☆ Porter q(≧▽≦q) | ldjam.com | Ludum Dare game jam