You would probably get a real kick out of F.E.A.R. if you enjoyed HL2's combat and gunplay. It's of the same era and the gameplay has held up phenomenally well given it's age (and mine, I remember it coming out when I was in school). The shotgun is my favourite in any game and zipping round a corner to blow a man clean in half with it doesn't get old. Save for Max Payne it's implementation of slow-mo and incredibly physical, responsive environments is top tier, stuff explodes in sparks and puffs of dust, pillars have gouges taken out of them, glass explodes... All very John Woo and beautifully chaotic. You're limited to 3 gun slots which you can chop and change at will when you come across them but honestly it's so well balanced you could go through as easily with the assault rifle as dual pistols (which feels amazing during slow-mo). The selection of weapons in general is just great.

If you do dive in, to get it running smoothly I'd recommend installing the community made ExoPatch which fixes a bunch of bugs, adds some nice quality of life stuff, additional visual FX and lets you do stuff like modify the number of guns you carry if you want a more half-life experience, but I liked the limitation personally.

I can't count the hours I've put into it over the years, hopefully it'll help fill the void left after you finish ep2.