Finally got a chance to sit down and place this. I really enjoyed this game. Here's some of the feedback I can think to give.
--- Graphics ---
The graphics were great. Reminded me a lot of the games done by "The Behemoth" like Castle Crashers, that sort of style. Having the controller on the tutorial screen was a nice touch as well. The different designs for the slims are really cool, especially that pesky yellow one (I swear I got hit more by them than the other colors lol)
--- Audio ---
Audio was really good. Music was great. Even though it was short and on a loop, it never felt repetitive. The narration in the tutorial screen as well as the call outs during the game were great. Seemed so dissapointed at me loosing my chain, but man did she get excited when I could cash in.
--- Controls --- You stated that it was better to play with a gamepad, and that is 100% accurate. The keyboard controls are pretty solid, and would be as good if there was some indication as to where the mouse was other than the direction of the sword pointing. Maybe a small dot or some type of non-intrusive reticle. I think that's all that would be missing for the mouse, just something to visually track separately from the sword direction
Moving and aiming with a gamepad is much better, but I it made my arm tired. I think it was because of having to constantly mash the right bumper. Typically with gamepad controls, buttons you mash a lot are in the A,B,X,Y buttons, so mashing the bumber was felt a bit odd. Maybe give the option to customize inputs?
--- Gameplay --- The game play was fun with the right amount of challenge. I noticed that some of the slimes would move faster and intentially run toward me while some just moved slowly toward me and some just sat still. It gave it a good depth and challenge to building the combos and trying to survive.
The risk / reward of building a chain was interesting, but I found myself sometimes killing slimes that I wasn't technically attacking. For instance, I could attack a yellow slime at my 45 degree angle, and one sorta next to it but closer to 90 degree angle from me was still getting hit, even thought he sword graphic wasn't touching it. I broke a few big chains because of that.
--- Overall --- Overall I really enjoyed this and hope that you continue working on it after Ludum and do a full release. You all did a good job.
--- Also high score --- Also, i believe i'm currently #1 on leaderboard with 863 :D high_score_863.png
Obligitory link to my game and asking to play/rate mine as well https://ldjam.com/events/ludum-dare/41/slime-battle-royale