hi again gabotico. the new sprites works for all those enemies are pretty good.
look, this is one idea i tought days ago...
how could be rat king? well, on both tv series from 80s and 2003, rat king uses his rats army for attack the turtles.
could be interesting if you like, that him can use as attack a group of rats. that you can stop by attack they. or must avoid depending of the attack.
also, if you want, you can do these rats could take the form you wanted.
for example, imagine a giant sling shot, a hammer... or a giant hand trying to stomp you... you know, things like that.
that is very typical on this kind of cartoon series and also in the konami games i think. and could result interesting.
rat king could attack you sending his rats on different attack patters, and then hide himself inside a place where you cannot enter.
and after the group of rats attacked you, he could get back for figth you again.
that could do the rat king battle more interesting and curious. but it will needs work and also imagination, for decide wich kind of attacks you could do the rats perform.
i know i saw this in other games, but now i cannot remenber where.
apart of this, also is clear that splinter should be one of their helpers.
and maybe when you beat him, he must join you as a cpu partner, or just stay in there on the ground, with his dizzy after the fight. and unable to fight more because you has beat him.
greetings master.
EDIT:
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hey!, talking about rats...
the mousers and baxter stockman flying machine, was never used as players neither.
if you wish to do something funny, you can add small playable enemies as they (or road kill rodney), etc. even when they cannot have too many attacks due to have only some few moves limitation.
this is like on the awesome "streets of rage 2 syndicate wars hack".
where all the enemies are playable. even when some doents have many possible attacks. (galsia dont have jump and his only attacks are take a knife and run, and do punches).
however, is very funny can play with him. and also is a challege try to pass many enemies or stages with a very limited playable chars like those...
greetings