Have you ever looked at the pycho kiss fps engine on dreamcast it look's as modable as most. It's based on the ‎Lithtech 1.5
engine..
Game's that ran on that engine are
1.0
Shogo: Mobile Armor Division by Monolith Productions (1998)
Blood II: The Chosen by Monolith Productions (1998)
1.5
KISS: Psycho Circus: The Nightmare Child by Third Law Interactive (2000)
Might and Magic IX by New World Computing (2002)
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For Half life dc
I could try to help with the dll's i downloaded all of them a wince version of the src. it should be possable to compile them as a sh4 target.\
No promise on this.. I dont have wince Dev kit set up right now, i have been doing kos..
I would like to see a mod for half life , that look's like quake 2
since quake 2 is a no go to fully port to dreamcast.. I'm sure something could be made to look like quake2 on half life dreamcast engine..
MY 2 cent's lol