Okay, first off, I am sorry. I feel like I didn't do a proper review of your game. I didn't even know there were other floors.
It seems that there is a bug where, sometimes, when it is time to go to another floor (aka, when the doors and item are supposed to appear), nothing happens instead. I was unlucky enough to get that on my first time clearing the first floor, so I just assumed that was the end of the game. Upon reading your reply, I realized something was off and went back (had the bug a couple more times on random floors too, but it seems to only happen sometimes without much preference for any specific floor).
As for the comboing, you are right, I did undervalue it. Taking your reply into account, I tried to use it more and rely more on the recovery times and timing to get around. It was a lot better. I think the main reason I didn't do it the first time around is because it didn't feel reliable when I was getting started. Far too often it just ended up being a trade of blows instead of me being able to deal damage and escape, specially against the half circle attack guy and the stab guy. A bit more of practice and understanding of the enemies did fix it though.
That said, I still feel like the half circle guy attacks you just a tad bit too fast when it manages to get close (I am mostly talking when there are 2 or more of them clumped up here). I say this because I noticed that this enemy in specific was the main (albeit no the only one) reason getting caught in a clump was basically death and that I had to rely on pure hit and run tactics against big clumps. The way it is now, their attacks pretty much lock you inside the clump (because they knock you back a bit and come really fast) and deal far too much damage in far too little time in that situation (like, you get hit once, the hit slows you down and suddenly that is enough for the same enemy to hit you 2 more times or just lock you inside the clump for the time being). Sometimes you get lucky and manage to land a half circle attack of your own to escape, but it is never guaranteed that it will work and it will certainly have cost you A LOT OF HEALTH before you escape. As such, I have two suggestions of how to balance it: Either reducing the base speed of attack so they don't lock you in or deal massive damage so easy and fast or giving the player some invincibility frames. Now, I kinda feel like the second one doesn't mesh too well with the current vibe of the game, so my first suggestion is my favorite.
It is interesting that you mention making them bump into each other because, as it is, I noticed them doing something like that sometimes, but in a very buggy way. Sometimes, specially when I used the stab (hitting several of the clumped up enemies) followed by the ball attack, one or two of them would "teleport" a bit (more like what you would expect of a game stutter, except everything was running normally, except of these guys and only for that moment). Since they just sorta of teleported, it was more frustrating than anything else, but a properly implemented version of that sounds like it would be a really cool feature.
Another small suggestion is that, when you stop moving the character keeps looking towards the direction that you were looking before right? Well, that only works for up, down, left and right currently. I think it would be cool if it could also keep looking diagonally when you stop. This can be useful for comboing in a diagonal since, currently, you can only combo that way if you keep advancing towards the enemy non stop, which isn't always smart.
As for the highest floor I reached, the first time it was the first (for obvious reasons) but, for the second, it was the boss floor (you said it is the 11th floor, right? I forget to look at the number in game XD). Haven't defeated the boss yet though. Can't seen to figure out how to damage them without it becoming (again) a trade of blows. Probably a skill issue if I am being honest XD.
As for combos, I find that adding stab to the end of nearly all of them works really well, mostly because, after the first few attacks, the enemy tends to have been knocked back a bit, so a ranged attack works well and, unlike the ball attack, it can actually hit several enemies at once, which is useful to prevent getting attacked by a second enemy while you are finishing your first combo. I find that is specially true for the A combo.
For the B combo I find that the tow shortest range attacks don't make sense so I try never adding them here. This is because the attacks already on this combo are already long ranged, so it is likely the enemy won't even be close enough to be hit by a short ranged attack when you are using it.
The C combo felt the me most flexible for me, on the sense that nearly all the attacks could be added here and it would result in a decent final combination. My favorite to add here was the stab though (less than with combo A, but still) and, once again, it was for a matter of range. The C combo starts with a mid low ranged attack, so following it by a mid high ranged attack means there is a better chance of the enemy being in range to get hit.
The D combo is one where I didn't really like to add anything other the more dashs. For me, that was more the dash button than anything else (also, if you add 2 dashes here you can get a very nice boost of speed for some fights). Now, to be fair, dashing and hitting with the half circle is a good strategy, but, since the enemies don't seem to get hampered in anyway by the dash itself (only by the attack that follows it), it always felt too risky. Unless your timing is good for it, you get hit, likely before you even hit you opponent, Maybe I am missing something (again), but that didn't feel like the most useful place to put the extra extra on the combo.
Another thing I didn't like to do was add a dash to combos A, B or C. This was mostly because I would be accidentally dashing into enemies even more often than I already do and taking lots of damage. I am not that good at it, so changing directions immediately while keeping track of the combo attacks and enemies was a tad bit too much for me.
With all that said, I am actually increasing my rating of this game. I liked it before, but now, with the extra floors (they feel like extra floors to me okay XD), it is considerably better in pretty much all aspects. Congratulations! Your game is really good!