also, I think the knowledge of how to manufacture alien alloys comes too easily. you simply get some alien stuff, your scientists take a look, and then they are able to replicate it perfectly? I don't think so.
I think that researching alien alloys should allow the use of alien alloys, but perhaps even that should be limited - maybe you recover "alien debris" instead, and have to extract usable pieces of alien alloys in order to make stuff out of it, at a rate of 3-to-1 or something?
only later, after interrogating an engineer or two, should you be able to actually manufacture alien alloys from ordinary raw materials.
about the lasers: I would think it totally believable if you would need alien alloys to research laser technology. perhaps the alloys are needed for lossless reflectors in the amplification chamber, as well as for the capacitors needed for the laser power cells.
another thing that comes to my mind: we could try and split the alien alloy research into several parts. for game-lore purposes, we could make the alien alloys into the holy grail of material sciences: stuff that, depending on the circumstances, can act as a perfect conductor, perfect insulator, super-strong yet lightweight building material, perhaps even as an energy converter (electrical-to-mechanical, heat-to-light, gravity-wave-shaping, whatever). the trick is that you don't discover all properties right away, but in stages. the different properties can then act as principles upon which other technologies are based (new weapons, new armor, etc.).
this way, one of the first properties discovered could lead to "conventional weapon improvements", another to "laser weapon research", and only later discoveries unlock stuff like plasma containment principles and UFO propulsion.
something like this:
[item: Alien Debris] --> (research: Alien Debris)
(research: Alien Debris) --> (discovery: Alien Alloys)
(discovery: Alien Alloys) --> (manufacture: Alien Alloy Salvaging) | "manufacture: Alien Alloy Salvaging" allows conversion of 3 units Alien Debris to 1 unit Alien Alloys
(discovery: Alien Alloys) --> (research: Alien Alloy Properties)
(research: Alien Alloy Properties) --> (discovery: Super-Strong Materials), (research: Further Alien Alloy Properties)
(discovery: Super-Strong Materials) --> (manufacture: <some advanced human weapons or ammo, armor, craft>)
(research: Further Alien Alloy Properties) --> (discovery: Alien Alloy Electrical Properties), (research: Even More Alien Alloy Properties)
(discovery: Alien Alloy Electrical Properties) --> (research: Advanced Power Systems)
(research: Advanced Power Systems) --> (discovery: Laser Weapons), (manufacture: <some other advanced human craft>)
(research: Even More Alien Alloy Properties) --> (discovery: Alien Alloy Power Conversion), (manufacture: >some other advanced weapons or other>)