When I have time to, I'm currently playing
Hurrican, a recently released Turrican inspired game by
Poke 53280, a veteran german hobbist game development team (Untergrund-spiele.de, anyone? I think I'm still member there too..). Hurrican features tons of particle effects, very nice graphics, cool music and a fun old-days like addictive gameplay. And totally free. It is a bit too difficult for me personally, maybe because it is only possible to save the game between levels, but this doesn't matter at all, maybe also because it is a bigger challenge this way.
This Hurrican youtube video shows the gameplay, but it is scaled down, so you won't see all the details. Cool game, nice work, poke53280! :)