BETA HISTORY
I've tested things over my history. There's three levels of testing: In-house development QA, Offsite Beta, Community/Open-Sourced Beta.

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HEROES (Opensource)
A little multi-platform game that resembled snake/tron with collectables. I tested the Windows platform and checked for incorrect level layouts. It's no longer around.

QuakeForge (Opensource)
A source port of Quakeworld that was based on accurate timing and general security features, I tested the general software SDL and WGL end of things. It stopped before 2004.

Terraria (1.4, Offsite Closed Beta)
I had been part of the general second-hand beta testing team for Terraria in 1.3.6, which was eventually transformed into 1.4; I have provided bug reports and confirmations as a player, however. Working with the team to get the major milestone released was a treat! I also have a unique painting which might appear in an abandoned house in world generation. That painting is "A Horrible Night For Alchemy". I am not part of the team right now since 1.4.1.

BOULDER DASH 40th ANNIVERSARY (Offsite Closed Beta, QA)
Not only was I the contributor of the Dangerdash caveset, I've also helped the team hone in on the classic Boulder Dash feel throughout the development process. I also helped unbreak their in-house BDCFF converter, which allowed Dangerdash to be imported almost faithfully. I'm now ensuring released updates work without hitches. I have no direct relationship with BBG Entertainment GmbH.