#1 Mercury Bow from Oni (PS2) fired a frozen mercury spike
#2 .223/12mm over under submachine gun from Red Faction (also on PS2) looks like an MP5
#3 Plasma rifle from Iain M. Banks' "Use of Weapons" an antique museum piece, but Zakalwe likes how it's balanced
#4 a Culture GSV (general systems vehicle) "Iain M Banks describes his Culture ships as follows:
Culture starships - that is all classes of ship above inter-planetary - are sentient; their Minds (sophisticated AIs working largely in hyperspace to take advantage of the higher lightspeed there) bear the same relation to the fabric of the ship as a human brain does to the human body; the Mind is the important bit, and the rest is a life-support and transport system. Humans and independent drones (the Culture's non-android individual AIs of roughly human-equivalent intelligence) are unnecessary for the running of the starships, and have a status somewhere between passengers, pets and parasites.
The Culture's largest vessels - apart from certain art-works and a few Eccentrics - are the General Systems Vehicles of the Contact section. (Contact is the part of the Culture concerned with discovering, cataloguing, investigating, evaluating and - if thought prudent - interacting with other civilisations; its rationale and activities are covered elsewhere, in the stories.) The GSVs are fast and very large craft, measured in kilometres and inhabited by millions of people and machines. The idea behind them is that they represent the Culture, fully. All that the Culture knows, each GSV knows; anything that can be done anywhere in the Culture can be done within or by any GSV. In terms of both information and technology, they represent a last resort, and act like holographic fragments of the Culture itself, the whole contained within each part.