According to Wikipedia (for whatever that's worth), here's how the Contra continuity works out:
Here is the list of the Contra games that are part of the official (original) Contra continuity, and the years the game is set in:
* Contra (2633)
* Super Contra / Super C (2634)
* Operation C (2635)
* Contra III: The Alien Wars (2636)
* Contra 4 (2638)[1]
* Contra: Hard Corps (2641)
* Contra: Shattered Soldier (2642, 2647)
* Neo Contra (4444)
Here is the list of the Contra games that are retconned from the official Contra continuity:
* Contra Force (1992)
* Contra: Legacy of War
* C: The Contra Adventure
---
"With the first link, the chain is forged. The first speech censored, the first thought forbidden, the first freedom denied, chains us all irrevocably." [...] The first time any man's freedom is trodden on, we're all damaged. - Captain Jean-Luc Picard
B*tch, meet reality. Reality, meet b*tch. - Me