XBLIG REPLACEMENT?

I am asking this on part of Ma-Bo, since XBLIG is shutting down. Would anyone happen to know what would be the best thing to use to replace this program at all? He is trying to make a STG/shmup game, but doesn't know what to use outside of XBLIG, so I thought I'd inquire on his behalf. ^^;

For those wondering, he's also from Japan so that's something else to keep in consideration, just in case. ^^;