What achievements / score / whatever I have to achieve to acquire striker gun?
You need to complete the Dexter Discordance escalation in Hokkaido.
Meaning if I don’t have Hitman 2016 pass bought, I can’t?
Yeah, sorry, you’d need access to the H2016 levels.
You can get El Matador if you have access to Santa Fortuna. That’s just as good I think.
All Hitman 3 unlocks are listed here Hitman 3 – Full List of Unlocks and Mastery Tracks
Hitman 1 Unlocks:
Hokkaido – Situs Inversus
- Striker (Pistol, Super Damage, Piercing) – Complete all levels of The Dexter Discordance Escalation Contract
Yeah, same gun, just a different skin.
Escalation Track 2
TRACK 2: Complete X escalations on Hawke’s Bay, Miami, Santa Fortuna, Mumbai, Whittleton Creek, Isle of Sgàil, New York, Haven Island
- Tier 10 (Complete 26 escalations): El Matador (Pistol, Super Damage, Piercing)
Sadly I don’t either. Although I do have both games bought (on Steam), but I’ve never managed to transfer the achievements from previous games.